Chair control

ABSTRACT

970,464. Resiliently mounted and adjustable seats. STEWART-WARNER CORPORATION. May 21, 1963 [May 22,1962], No. 20249/63. Headings A4J and A4U. A chair control for supporting a chair back tiltably relative to its seat, comprises relatively pivotally mounted separate back and seat supports 12, 10, respectively, and a torsion bar 18 fixed at or near its ends in non-rotatable relationship with one of the supports and fixed intermediate its ends in a non- rotatable relationship with the other of the supports, thereby providing resilient restraint against tilting between the two supports. The seat support 10, which is carried by a post 13, includes a channel shaped cross member 26, spider arms 42 and plates 44. The back support 10 comprising a body 52 and hinge 68 extends through an opening in the cross member 26 so that the torsion bar 18, which is of square cross section, can be secured in square openings in the plates 44, pivotally supported in bushings 56, on body 52, and engaged in a square opening in a torque lever 22. The initial torque on the bar 18 is adjusted by a wheel 64 having a threaded stud engaging in body 52 and bearing against the end of the lever 22, subsequent rearward force on the chair back tilting the body member 52 to increase the torque and, consequently, the restoring force. The back, which is connected to arm 17, is vertically adjustable by sliding a clamping bolt in a slot 81 in hinge member 68 and is angularly adjustable, by pivoting the member 68 about a rivet 70 under control of a locking bolt 73 movable in slots 78 in body 52.

H. w. PARROTT CHAIR CONTROL June 9, 1964 Filed May 22, 1962 2 Sheets-Sheet 1 A 1 /o/-ne/ June 9, 1964 H. w; PARROTT 3,136,580

CHAIR CONTROL a Filed May 22, 1962 2 Sheets-Sheet 2 United States Patent 3,136,580 CHAIR CONTROL Henry Wheeler Parrott, Shelton, Conn., assignor to The Bassick Company, Bridgeport, C0nn., a corporation of Connecticut Filed May 22, 1962, Ser. No. 196,770 8 Claims. (Cl. 297-304) This invention relates to a chair control for supporting a chair back tiltably relative to its seat, and in particular, to a chair control of the type having a torsion bar providing spring action between the relatively tiltable chair back and seat.

An object of this invention is to provide a chair con trol for supporting the chair seat firmly relative to the chair base and for supporting the chair back tiltably relative to the chair seat.

Another object of this invention is to provide a chair conrol having few component parts fabricated and assembled at a minimum cost.

Another object of this invention is to provide a. chair control having a spring action readily adjustable to various degrees of liveliness to satisfy substantially all invidual requirements.

A particular feature of this chair control is a torsion bar interconnecting the respective support structures for the chair seat and the chair back. The torsion bar is fixed at its opposite ends relative to one of the support structures and is fixed at its intermediate portion relative to the other of the support structures. Spring action between the chair back and chair seat thus occurs by flexure of the torsion bar in opposite rotational directions from its intermediate portion to its opposite ends.

In order that these objects can be fully appreciated and understood, reference is herein made to the accompanying drawings, wherein:

FIG. 1 is a perspective view of the subject chair control as seen from the top and front side of the control;

FIG. 2 is a top. plan view of the chair control of FIG. 1;

FIG. 3 is a view as seen generally from line 3-3 of FIG. 2;

FIG. 4 is an end elevational view as seen generally from line 44 of FIG. 2;

FIG. 5 is a section view as seen generally from line 55 of FIG. 4;

FIG. 6 is a perspective view of a bushing member used in the subject control; and

FIG. 7 is a side elevational view of the subject con trol in its relationship with a typical posture chair.

Referring now to the drawings and in particular to FIGS. 1 and 7, the subject chair control is seen to include a seat support 10 and a back support 12 which is tiltable relative to the seat support 10. The seat support 10 is mounted on post 13 connected at its lower end to a chair base 14 adapted to support the chair on the supporting floor. The seat 15 is mounted on the seat support 10 and held generally firm relative to the base 14. The back 16 is supported by the back support 12, as through arm 17, and is tiltable resiliently relative to the seat 15.

A torsion bar or torque rod 18 is fixed at its ends relative to the seat support 10 and extends intermediate its ends rotatably through bearing structure 20 supported by the seat support. The back support 12 is mounted on the bearing structure 20 to pivot thereabout relative to the seat support 10. The torque rod 18, keyed intermediate its ends to a torque lever 22 coupled to the back support 12, is operable to bias the back support in the direction corresponding to the most forward position of the chair back 16 with respect to the seat 15. Upon an occupant of the chair leaning rearwardly on the back 16,

tilting of the back relative to its seat 15 is resiliently resisted by the torsional force of torque rod 18 acting between the back support 12 and the seat support 10.

Referring to the construction of the subject chair control,,the seat support 10 includes a generally U-shaped channel or cross member 26 having side Walls 27 and 28, and interconnecting Wall 29. Spaced ears 30 are bent from the interconnecting wall 29 to provide supports for bearing structure 20. A flanged hub member 33 (FIG. 3) is secured as by riveting (not shown) to the wall 29 between the ears 30. The hub has bore 34 disposed in alignment with a central opening 35 in the wall adapted to receive the upper portion of post 13. The forward side wall 27 V-notched from the ends toward the center presents a forward stop 36 (FIG. 3) intermediate the laterally spaced ears 30. The rearward side wall 28 has an opening 37 (FIG. 3) to receive the back support 12, a rearward stop 38 defining the lower edge of the opening. The back support 12 pivots about the bearing structure 20 until abutment with the forward stop 36 or the rearward stop 38.

Spider arm 42 and a torque rod housing plate 44 are secured to each end of the cross member 26. Although the arm 42 and the plate 44 are separate, they abut one another along a generally complementary contour 87. The spider arm 42 is a right angle member having a top portion 45 and a side Web 46. As seen in FIGS. 4 and 5, the ends of cross member 26 have lugs 48 which are received within complementary receiving openings of the arms 42 and plates 44 and hot riveted thereto. The rod housing plates 44 are provided with square openings 49 aligned with each other and the bearing structure 20 for non-rotatably receiving the square torque rod 18. The ends of the rod 18 are thus securely fixed relative to chair seat 15.

The back support 12 includes a body member 52 of U-shaped channel section having side walls 53 and an interconnecting wall 54. The body member 52 is posi tioned between the spaced cars 30 formed on the seat support 10. The ears 30 and the opposing side walls 53 of the body member have openings (not shown) of similar diameter, the openings being alignable on a single transverse axis. A bushing member 56 (FIG. 6), of nylon or some similar material, has a cylindrical hearing portion 58 receivable within each of the openings in the respective side wall until flange 59 abuts thereagainst. The bushings 56 are positioned in back-to-back relationship, as seen in FIG. 2, so that the flanges 59 are adjacent one another to space the body member 52 from the ears 30. The torque rod 18 received within the aligned internal bores 61 of the bushings 56 main tains the bushings in the respective positions to form the bearing structure 20. The bearing structure thus both rotatably supports the intermediate portion of the torque rod 18 and pivotally supports the body member 52 to the cross member 26. I

The torque lever 22 is positioned between laterally spaced guides 62 on the wall 54 of body member 52. The square torque rod 18 is complementary to the square openings 63 in the torque lever 22, as seen in FIG. 3, thereby providing for economical keying together of the members. A hand wheel 64 having a stud 65 thread ably received within tap 66 and bearing against the free end of the lever 22 operates to adjust the intial torque on the rod 18. t

A hinge member 68 is supported at the rearward end of the body member 52 for supporting the back arm 17. Patent No. 2,093,319 issued September 14, 1937, to W. F. Herold and entitled Posture Chair discloses a typical hinge member. Basically, however, the hinge 68 is generally U-shaped and has spaced side Walls 69 adapted to overlap and to engage frictionally the side walls 53 of the body member 52. The hinge is pivoted I by rivet 70 to the rear of the body member and is frictionally held in a plurality of adjusted angular positions by means of lock assembly 72 including a bolt 73, washer 74 and threaded bore T-member '75 theradable onto the end of bolt '73. The lock assembly 72 extends through crossed slots 77 and 78 disposed in the side walls of body member 52 and hinge 68. The slots 77 and 78 cross each other only once, but at various movable distances from the rivet 70 depending on the angle of tilt of the hinge 68 relative to the body member 52. The lock assembly sliding within the slots thus tiltably adjusts the hinge 68 relative to the body member 52. The center wall 80 of the hinge 68 has a vertical slot 81 for receiving a locking assembly bolt, as is well known in the art, by which the arm 17 is adjustable in the vertical direction for height adjustment of the chair back 16.

To provide adequate strength for securing the fixed ends of the torque rod 18, it might be desirable to increase the thickness of the securing members to present a greater area engagement of each member with the torque rod. As shown, the rod' housing plate 44 is of slightly heavier gauge than the web 46 of the spider arm 42. The difference in thickness of the members produces a ledge 83 (FIGS. 1 and 5). The end of the cross member 26 has a shoulder 85 that abuts the ledge 83 when the spider arm 42 and rod housing plate 44 are assembled in position. The rod housing plate 44 thus is fixed securely to the cross member 26 at four spaced locations as determined by the spaced lugs 48 received snugly Within the plate, and the abutment of the ledge and shoulder. Similarly, each spider arm is firmly secured to the cross member 26 at the locations as deter' mined by the spaced lugs 48 and at a third location as determined by the flush contact along contour 87 with the housing plate 44. Thus, the seat support can be a unitary structure economically formed from the cross member 26, the spider arms 42 and the rod housing plates 44.

The control can be assembled in the following general manner. The seat's'upport 10 including the cross member 26, spider arms 42 and 'rod housing plates 44 can be fabricated as a single unit as above noted. The back support 12 including the body member 52 and hinge 68 is positioned through the opening 37 in the cross member 26 until the bushings 56 in the respective side walls are aligned. In the aligned position, the torque rod 13 can be manipulated through the square receiving openings 49 in the housing plates, the internal bores- 61 of the bushings 56, and the fitted opening 63 of the torque lever 22 until it is centered within the seat support. A lock washer 88 having a center opening defined by spring fingers can be positioned on each projected end of the torque rod 18 to maintain the rod centered.

The resiliency of the control can be adjusted by the hand wheel 64 to prestrain the rod 18 to a greater or lesser extent. Thus the body member 52 in the normal position is in direct contact with stop 36 on the cross member 26. A rearward force on the chair back tilts the body member in a clockwise direction as seen in FIG. 3. This tilting causes the body member 52 to act against the torque lever 22, thereby further twisting the rod 18 in opposite rotational directions from its center toward its ends to increase the spring return force on the back. In the position as shown in FIG. 3 the rod is near the least prestrained position for the easiest spring action, whereas the position with the handwheel stud further threaded in the 'tap'66 corresponds to a stiffer more lively spring action. Stop 38 limits rearward tilting of the body member relative to the seat.

It will be noted that the subject control supports the chair seat firmly on the chair base 14. However,

the chair back 16 being cantilevered on the back support 7 12 pivoted between the closely spaced ears 30 within the generally resilient bushings 56, is slightly flexible laterally.

d Thus, though the seat is firm, the back flexes laterally a slight degree to give a pleasingsense of freedom and comfort to the occupant.

The particular construction of the subject control not only requires few moving parts, but also utilizes components which can be fabricated ecomom'cally. Similarly the components are joined together in a manner particularly adaptable for mass production techniques. Thus the subject control is both simple and economical.

Although only a specific embodiment of the subject chair control has been shown, modifications can be made therein without departing from the true concept of this inventive disclosure. Thus, it is desired that the invention is not limited by the embodiment shown herein, but by the scope of the appended claims.

What is claimed is:

1. A chair control for supporting a chair back tiltably relative to its seat, comprising in combination, seat support structure for supporting the chair seat, back support structure for supportingthe chair back, means mounting the back support structure on the seat support structure for limited tiltable movement relative thereto, a torsion bar, means for securing the torsion bar at each of its opposite ends nonrotatably relative to the seat support structure, and means for securing the torsion bar intermediate its ends nonrotatably relative to the back support structure.

2. A chair control for supporting a chair back tiltably relative to its chair seat, comprising in combination, support structures adapted to be secured, respectively, to the chair seat and to the chair back for support thereof, means mounting the support structures to pivot relative to one another about a given rotational axis, an elongated torsion bar, means at each of the opposite ends of the torsion bar operable to secure said opposite ends in fixed nonrotatable relationship relative to one of the support structures, and means intermediate the opposite ends of the torsion bar operable to couple said intermediate portion of the torsion bar in fixed nonrotatable relationship relative to the other of the support structures.

3. A chair control for supporting a chair back tiltably relative to its seat, comprising in combination, a seat support having a pair of transversely spaced members adapted for connection to the seat, a torsion bar extending between the spaced members and being fixed at each of its opposite ends nonrotatably within the corresponding spaced member, a back support adapted for connection to the chair back, said back support being pivotally coupled to structure fixed relative to the spaced members to pivot about an axis of rotation generally the same as the longitudinal axis of the torsion bar, and means coupling the torsion bar at its intermediate portion nonrotatably to the back support operable to twist said torsion bar upon pivotal movement of the back support.

4. A chair control for supporting a chair back tiltably relative to its seat, comprising in combination, seat support structure for supporting the chair seat and having a cross member and a pair of spaced members connected fixedly to the opposite ends thereof, a torsion bar fixed at each of its opposite ends in nonrotatable relationship relative to the spaced members, bearing structure supported by the cross member between the spaced members, back support structure for supporting the chair back and tiltably mounted on the bearing structure, and means coupling the torsion bar intermediate its ends to the back support structure in fixed nonrotatable relationship relative thereto operable to cause flexure of the torsion bar upon relative tilting of the seat and back support structures.

5. A chair control for supporting a chair back tiltably relative to its seat, comprising in combination, seat support structure adapted to support the chair seat and having a cross member and a pair of spaced end members connected to the opposite ends of the cross member, a torsion bar fixed nonrotatably at each of its opposite ends to the respective end members, bearing structure supported by the cross member between the spaced members, back support structure adapted to support the chair back and being pivotally supported by the bearing structure, and a lever keyed to the torsion bar intermediate its ends and abutting the back support operable to cause fiexure of the torsion bar in opposite rotational directions from its intermediate portion to its ends upon relative tilting of the seat and back support structures.

6. A chair control for supporting a chair back tiltably relative to its chair seat, comprising in combination, sup port structures adapted to be secured, respectively, to the chair seat and the chair back for support thereof, pivot structure supporting the support structures to tilt relative to one another about a given axis of rotation fixed relative to each of said support structures, an elongated torsion bar fixed at each of its opposite ends in nonrotatable relationship with respect to its longitudinal axis relative to one of the support structures, and coupling structure fixing the torsion bar intermediate its opposite ends in nonrotatable relationship with respect to its longitudinal axis relative to the other of the support structures, the torsion bar being operable upon tilting of the support structures relative to one another to twist in opposite rotational directions relative to its longitudinal axis from its intermediate portion toward its opposite ends.

7. A chair control for supporting a chair back tiltably relative to its chair seat, comprising in combination, seat support structure for supporting the chair seat and including a cross member, a pair of spaced end members each secured rigidly to an opposite end of the cross member, bearing support structure on the cross member intermediate the end members, back support structure for supporting the chair back and including a body member extending transverse to the cross member proximate the bearing support structure, bearing means for pivotally supporting the body member to the cross member and including annular bushing structure received in aligned openings in said bearing support structure and the body member, a torsion bar received intermediate its ends in the bushing structure and supported rotatably therein, the opposit ends of the torsion bar projecting to the spaced end members and being fixed thereby against rotation relative thereto, and means coupling the body member to the torsion bar intermediate its ends operable to flex the torsion bar upon relative pivotal movement of the body member and cross member.

8. A chair control according to claim 7, wherein said coupling means includes a lever keyed nonrotatably to the torsion bar intermediate its ends, and adjustable means between the body member and lever operable to interconnect adjustably the body member and the torsion bar intermediate its ends for related movements.

References Cited in the file of this patent UNITED STATES PATENTS Soderberg Ian. 12, 1957 

1. A CHAIR CONTROL FOR SUPPORTING A CHAIR BACK TILTABLY RELATIVE TO ITS SEAT, COMPRISING IN COMBINATION, SEAT SUPPORT STRUCTURE FOR SUPPORTING THE CHAIR SEAT, BACK SUPPORT STRUCTURE FOR SUPPORTING THE CHAIR BACK, MEANS MOUNTING THE BACK SUPPORT STRUCTURE ON THE SEAT SUPPORT STRUCTURE FOR LIMITED TILTABLE MOVEMENT RELATIVE THERETO, A TORSION BAR, MEANS FOR SECURING THE TORSION BAR AT EACH OF ITS OPPOSITE ENDS NONROTATABLY RELATIVE TO THE SEAT SUPPORT STRUCTURE, AND MEANS FOR SECURING THE TORSION BAR INTERMEDIATE ITS ENDS NONROTATABLY RELATIVE TO THE BACK SUPPORT STRUCTURE. 